When wind turbines are operated in cold-weather climates, the potential build-up of ice on the wind turbine blades presents challenges for turbine performance. In a first aspect, any ice formation on the blade surfaces will disrupt the blade aerodynamics, which may lead to a reduction in turbine efficiency and/or increased operational noise levels. In a further aspect, ice which breaks away from blade surfaces can present a falling hazard. In this regard, wind turbine blades in such locations are often provided with systems to deliver ice prevention and/or removal.
In addition to electrical heating systems embedded in blades and mechanical de-icing systems, it is known to provide hot-air de-icing systems which operate on the principle of supplying heated air to the interior of a wind turbine blade, to raise the surface temperature of the blade to above freezing. An example of such a hot-air de-icing system can be seen in US Patent Application Publication No. US 2013/0106108.
However, such prior art hot air systems are often inefficient, and can require large amounts of energy to ensure that ice is prevented from forming at the tip end of the wind turbine blades, where the impact of any ice formation on the blade aerodynamics is most significant. Furthermore, the use of such hot air systems can introduce additional complications in terms of increased blade weight and/or structural strain, which can affect the practicability of such solutions.
It is an object of the invention to provide a de-icing system that provides improved performance over the prior art.